Chronic urticaria (CU) is a common skin disorder affecting 0.1 to 1% of the general population. It is characterized by recurrent, transitory, pruritic erythematous wheals on a patient's skin for approximately 6 weeks or longer. The impact of CU on the quality of life is significant. It has been demonstrated that in 30-50% of these CU patients there is an auto-immune etiology with auto-antibodies against IgE, FcεRI or FcεRII (CD23). These auto-antibodies are presumed to bind to the surface of mast cells and basophils, which initiates a signal transduction cascade that results in the secretion of histamine and other mediators.
The treatment course for those with auto-immune forms of CU is often different than for acute and transient CU (or idiopathic CU). Drugs that modulate the basic immunological aspects of the disease (e.g., methotrexate, calcineurin inhibitors, etc.) may be considered if an auto-immune etiology is established, whereas such drugs may not be useful in treating other forms of CU. Accordingly, there is a need for robust, reliable, accurate, and efficient methods for diagnosing auto-immune forms of CU.